Galvanic isolator provides a mean for moving a signal from one electrical circuit to another electrical circuit that must otherwise be electrically isolated from one another. Usually the two electrical circuits operate at different voltages and need to be electrically isolated. For example, consider an application in which a 5V battery powered controller board is used to control a motor circuit operating at 240V. In this example, it is essential to electrically isolate the 240V motor circuits from the 5V controller circuit while allowing the 5V controller circuit to send or receive signals from the 240V motor circuit. In this type of application, a galvanic isolator may be used to provide voltage and noise isolation while allowing the information exchange between the two circuit systems. For electrical system involving more than two circuits operating at different voltages, a multi-channel galvanic isolator may be used.
There are three main types of galvanic isolators. The first type is wireless radio frequency transceiver in which a signal is sent across from one circuit to another circuit through wireless signal. The second type is magnetic isolator in which the signal is transmitted over through magnetic field. The third type is optocoupler in which the signal is transfer through light waves. As galvanic isolators may be used in application involving voltage operating at kilo Volts, magnetic isolators and radio frequency isolators may have limitation in shielding noise from one circuit system to another circuit system. On the other hand, optocouplers, coupling signal through light waves, do not induce noise as per magnetic isolators or radio-frequency transceivers.
Generally, an optocoupler comprises an optical transmitter die and an optical receiver die. The optical transmitter die and the optical receiver die may be housed in one package. A multi-channel optocoupler may have more than one pair of optical transmitter or receiver dies, for example a plurality of optical transmitter and receiver dies.